The innovative apparatus sprang up in 1997, when inventor Bertram Rohloff devised it as a way of skirting city street-vendor permits in the city. Without permits, "neither the grill nor the sausages could touch the ground."

As he worked on the invention, Mr. Rohloff considered everything from burning charcoal to hooking the grill up to a car battery — which he rejected because it would run down in just 10 minutes — before settling on propane. He designed it with an automatic cut-off mechanism for the gas, to ensure that it was safe in the event of an accident

According to the story, the Grillwalker franchise has become a common sight in the capital and Mr. Rohloff has hired subcontractors to wear the grills in other German cities.